Optical disc driving device

ABSTRACT

An optical disc driving device has a metallic exterior casing composed of a first casing and a second casing and an internal unit to be housed in the exterior casing. The internal unit includes an optical pickup unit having an optical pickup part that moves in radial directions of an optical disc to perform recording or reproduction of information signals on the optical disc. At a portion where the optical pickup part moved radially outward of the optical disc makes a closest approach to, in either one of the first casing or the second casing opposed to the first casting, a protrusion for electrically connecting the first casing and the second casing to each other is provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application of International Application No.PCT/JP2012/000183, with an international filing date of Jan. 13, 2012,which claims priority of Japanese Patent Application NO.: 2011-031596filed on Feb. 17, 2011, the content of which is incorporated herein byreference.

BACKGROUND

1. Technical Field

The technical field relates to an optical disc driving device forperforming recording or reproduction on an optical disc.

2. Description of Related Art

Conventionally, optical disc drive devices for performing recording orreproduction of information on optical discs such as DVDs and Blu-rayDiscs (BDs) are mounted on electronic equipment such as game equipment,recorders and players.

This type of optical disc drive device has an internal unit including anoptical pickup unit for performing optical recording or reproduction onan optical disc, a rotation drive device for driving rotation of anoptical disc, a moving mechanism for moving the optical pickup unit inradial directions of an optical disc, and the like. Also, the opticaldisc drive device has an electroconductive, metallic exterior casing forhousing the internal unit.

In information recording/reproducing devices such as hard disks, asshown in Japanese Patent Application Publication No. 2001-291985A,conventionally, an internal unit is housed in a metallic exterior casingfor purposes of dust prevention for the internal unit and shieldingoutward radiation noise. Also in optical disc drive devices, theinternal unit is housed in a metallic exterior casing from the samereasons.

In cases where the exterior casing of the optical disc driving device ismade up of a plurality of components, there is a need for takingmeasures against radiation of noise radiated from between the pluralityof components to outside.

Accordingly, an object of the present invention is to reduce noiseradiated outside from between a plurality of components constituting theexterior casing of the optical disc driving device.

In one general aspect, the present disclosure describes an optical discdriving device having: a metallic exterior casing composed of a firstcasing and a second casing; and an internal unit to be housed in theexterior casing, the internal unit including an optical pickup unithaving an optical pickup part that moves in radial directions of anoptical disc to perform recording or reproduction of information signalson the optical disc, wherein at a portion, which the optical pickup partmoved radially outward of the optical disc makes a closest approach to,in either one of the first casing or the second casing. Opposed to thefirst casing, a protrusion for electrically connecting the first casingand the second casing to each other is provided.

According to the present disclosure, electrical conduction between thefirst casing and the second casing, which constitute the exteriorcasing, can be ensured enough so that release of radiation noise frombetween the first casing and the second casing to outside can bereduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing an appearance of an optical discdrive device according to an embodiment;

FIG. 2 is an exploded perspective view showing a state in which theexterior casing is exploded;

FIG. 3 is a schematic plan view showing a schematic structure of aninternal unit of the optical disc drive device;

FIG. 4 is a plan view showing a state in which the internal unit ishoused in a first casing;

FIG. 5 is a sectional view showing part of a completed structure inwhich with the first casing and a second casing set up, the internalunit is housed in the exterior casing;

FIG. 6 is a perspective view showing a positional relationship betweenthe first casing and a printed wiring substrate of a control circuitblock;

FIG. 7 is a perspective view showing a state in which the printed wiringsubstrate is excluded in FIG. 6;

FIG. 8 is a schematic sectional view showing a structure of aninterfacing connector portion in the control circuit block; and

FIG. 9 is a schematic view showing a contact state between a fringeportion of an opening of the first casing and a ground pattern of theprinted wiring substrate.

DETAILED DESCRIPTION

Hereinbelow, an embodiment of the present disclosure will be describedwith reference to the accompanying drawings.

FIG. 1 is a perspective view showing an appearance of an optical discdrive device according to an embodiment of the disclosure. FIG. 2 is anexploded perspective view showing a state in which the exterior casingis exploded. As shown in FIGS. 1 and 2, the optical disc drive device ismade up with an internal unit 2 housed in an electroconductive, metallicexterior casing 1 having a disc insertion opening 1 a. The exteriorcasing 1 also serves a role as a shield for reducing outward release ofradiation noise generated from the internal unit 2.

The exterior casing 1 is composed of a quadrilateral box-like firstcasing 3, and a quadrilateral lid-like second casing 4 which is put onthe first casing 3 so as to cover an upper opening portion of the firstcasing 3 and which has a front portion 4 a with the disc insertionopening 1 a formed therein. The internal unit 2 can be housed in theexterior casing 1 by first doing temporary fixing, i.e. hanging of thefront portion 4 a of the second casing 4 to a front portion of the firstcasing 3, then putting a rear portion of the second casing 4 on a rearportion of the first casing 3, and subsequently screwing the rearportion of the second casing 4 to the rear portion of the first casing 3with screws 5.

As shown in FIG. 2, fixing portions 3 a each having a screw hole towhich a screw 5 is tightened are provided in the upper opening portionof the first casing 3. At portions of the second casing 4 correspondingto those fixing portions 3 a, through holes 4 b through which the screws5 are to be inserted are provided, respectively. The screws 5 areinserted through the holes 4 b of the second casing 4, respectively, soas to be tightened to the screw holes of the fixing portions 3 a of thefirst casing 3.

Further, as shown in FIG. 2, a plurality of fitting portions 3 b eachhaving a screw hole to which a screw is tightened to fix the internalunit 2 into the first casing 3 are formed in a bottom face of the firstcasing 3.

The exterior casing 1 can be made by molding a sherardized steel sheethaving a thickness of 0.4 mm to 0.5 mm. In particular, the first casing3 can be made by using, for example, thin-plate sheet metal or the likeof a copper sheet, tin sheet, stainless sheet or the like having athickness of 0.2 mm to 0.3 mm. In addition, when rust-proofing propertyis considered preferentially important, tin plates or stainless sheetsare preferably used. In addition, with cost regarded as anotherimportant factor, tin plates are preferably used.

FIG. 3 is a schematic plan view showing a schematic structure of theinternal unit of the optical disc drive device. As shown in FIG. 3, theinternal unit 2 has, in a metallic unit housing 2 a, a spindle motor 6for holding a center of an optical disc and rotating the disc at highspeed, a disc insertion mechanism 7 for guiding an optical disc insertedthrough the disc insertion opening 1 a to the spindle motor 6, anoptical pickup unit 8 for performing recording/reproduction ofinformation signals on an optical disc, and a control circuit block 11having a printed wiring substrate 10 electrically connected via aflexible wiring substrate 9 to electronic components of the opticalpickup unit 8.

The disc insertion mechanism 7, under control by the control circuitblock 11, introduces an optical disc inserted through the disc insertionopening 1 a into the internal unit 2 and guides the optical disc to thespindle motor 6 so that the center of the optical disc is aligned with arotating shaft of the spindle motor 6.

The optical pickup unit 8 has an optical pickup part 8 a on which asemiconductor laser device and an optical lens for applying light of aspecified wavelength to an optical disc rotated by the spindle motor 6are mounted, guide shafts 8 b for holding the optical pickup part 8 a sothat the optical pickup part 8 a can be moved linearly in radialdirections of the optical disc, and a tracking mechanism for moving theoptical pickup part 8 a in a radial direction of the optical disc. Thetracking mechanism has a gear part 8 c provided in the optical pickuppart 8 a, and a rotating shaft 8 d meshing with the gear part 8 c. Asthe rotating shaft 8 d is rotated under control of the control circuitblock 11, the optical pickup part 8 a is moved in a radial direction ofthe optical disc via the gear part 8 c.

The guide shafts 8 b of the optical pickup unit 8 as well as therotating shaft 8 d of the tracking mechanism are held by holding parts 2b provided in the unit housing 2 a.

The control circuit block 11 is made up so that a microcomputer or othersemiconductor integrated circuit element 11 a and its peripheralcircuits are mounted on the printed wiring substrate 10 while aninterfacing connector 11 b for transmission and reception of electricalsignals from and to external electronic equipment (not shown) is mountedthereon. The semiconductor integrated circuit element 11 a of thecontrol circuit block 11 controls the spindle motor 6, the discinsertion mechanism 7, and the optical pickup unit 8, and also processessignals for information writing onto an optical disc via the opticalpickup unit 8 or signals read from an optical disc. Signals are alsodelivered and received between the control circuit block 11 and externalelectronic equipment via the interfacing connector 11 b.

Further, on the printed wiring substrate 10 of the control circuit block11, a ground pattern 10 a is formed so as to surround the connector 11 bmounted on the printed wiring substrate 10. Whereas the printed wiringsubstrate 10 is made by alternately stacking electrically conductivelayers of copper foil or the like and insulating layers of epoxy resinor the like, the ground pattern 10 a can be formed by cutting out partof the insulating layers of the printed wiring substrate 10 so that theconductive layers are exposed.

The ground pattern 10 a, as will be described later, has through holes10 b formed therein for insertion of screws serving to electricallyconnect the ground pattern 10 a and the first casing 3 of the exteriorcasing 1 to each other and to mechanically fit the printed wiringsubstrate 10 to the first casing 3. Further, another ground pattern (notshown) is provided at an end portion of the printed wiring substrate 10.Also provided are through holes 10 c for electrical connection of theexterior casing 1 and the unit housing 2 a to each other via the anotherground pattern as well as for mechanical fitting of the printed wiringsubstrate 10 to the unit housing 2 a (see FIG. 3).

FIG. 4 is a plan view showing a state in which the internal unit ishoused in the first casing. As shown in FIG. 4, the internal unit 2 ishoused in the first casing 3 so that the printed wiring substrate 10 ofthe control circuit block 11 is positioned on the bottom side, and theinternal unit 2 is fitted to the fitting portions 3 b in the bottomportion of the first casing 3 with screws (not shown). It is noted thatas shown in FIG. 4, the internal unit 2 is fitted to the first casing 3in a state reversed from the state shown in FIG. 3.

FIG. 5 is a sectional view showing part of a completed structure inwhich with the first casing 3 and the second casing 4 set up, theinternal unit is housed in the exterior casing.

As shown in FIGS. 4 and 5, a protrusion 3 c is provided at a portion ofthe first casing 3 to which the optical pickup part 8 a moved radiallyoutward of the optical disc makes its closest approach, i.e., at aportion of a rear-side side wall fixed with the two screws 5. In thisembodiment, the protrusion 3 c is provided, specifically, at a centralportion of the side wall of the first casing 3 to which the opticalpickup part 8 a makes a closest approach and which corresponds to anintermediate position of the two screws 5.

This protrusion 3 c, which protrudes outward, comes into contact with aside wall 4 c of the second casing 4 when the second casing 4 is fittedto the first casing 3. As a result, the protrusion 3 c and the secondcasing 4 are electrically connected to each other. The protrusion 3 c isformed by extruding part of the side wall of the first casing 3.Alternatively, the protrusion 3 c may be formed by forming two slitsparallel to part of the side wall of the first casing 3 and furtherbending a portion between the two slits. Furthermore, the protrusion 3 cmay also be formed by fitting another metallic member to the side wallof the first casing 3 by welding or brazing or the like. In addition,although FIGS. 4 and 5 show one example in which one protrusion 3 c isformed, a plurality of protrusions 3 c may also be formed in the sidewall to which the optical pickup part 8 a makes the closest approach.

The reasons that such a protrusion 3 c is provided are described below.Such an optical disc drive device as shown in FIGS. 1 to 5, in which theinternal unit 2 is housed in the exterior casing 1 composed of the firstcasing 3 and the second casing 4, has been under a demand for downsizingas electronic equipment containing the optical disc drive device getsdownsized more and more. For downsizing of the optical disc drivedevice, such measures are implemented as reduction of clearances betweenthe internal unit 2 and the exterior casing 1, thinning of the exteriorcasing 1, simplification of the assembling structure of the exteriorcasing 1, and the like.

However, with the optical disc drive device downsized, it would occur,in some cases, that a central portion of the side wall of the firstcasing 3 to which the optical pickup part 8 a, when moved to anoutermost peripheral portion of an optical disc, makes a closestapproach, and/or an opposing central portion of the side wall 4 c of thesecond casing 4 is flexed. That is, it might occur heretofore that anunfixed portion corresponding to an intermediate position between thetwo screws 5 is flexed. Moreover, such flexure might cause occurrence ofa gap between the side wall of the first casing 3 and the side wall 4 cof the second casing 4.

With occurrence of such a gap, an elongate hole is formed so as toextend from one screw 5 toward the other screw 5, so that electricalconduction between the first casing 3 and the second casing 4 can nolonger be secured enough due to the elongate hole. Then, radiation noisebecomes more likely to leak from between the side wall of the firstcasing 3 and the side wall 4 c of the second casing 4, i.e., through theelongate hole.

Accordingly, the protrusion 3 c is provided at a central portion of therear-side side wall of the first casing 3, to which the optical pickuppart 8 a makes its closest approach, as shown in FIGS. 4 and 5, so thateven upon the closest approach of the optical pickup part 8 a, theelectrical connection between the first casing 3 and the second casing 4can be maintained. More specifically, the protrusion 3 c is provided inthe first casing 3 so that when the second casing 4 is fitted to thefirst casing 3, the protrusion 3 c presses the side wall 4 c of thesecond casing toward the outside.

According to the structure having such a protrusion 3 c as shown above,even with the optical disc drive device provided in a downsized scale,electrical conduction between the portion of the side wall of the firstcasing 3 to which the optical pickup part 8 a makes its closest approachand the opposing portion of the side wall 4 c of the second casing canbe secured enough. As a result, outward release of radiation noise frombetween the first casing 3 and the second casing 4 can be reduced.

Preferably, as shown in FIG. 3, the optical pickup unit 8 is so placedthat the optical pickup part 8 a is moved toward the side wall 4 copposed to the disc insertion opening 1 a in the same direction as theoptical-disc insertion direction. Alternatively, the optical pickup unit8 may also preferably be so placed that the optical pickup part 8 a ismoved in a direction perpendicular to the optical-disc insertiondirection. As a result, leakage of radiation noise to the outsidethrough the disc insertion opening 1 a can be suppressed.

Also, the protrusion 3 c may be formed not so that the protrusion 3 cprotrudes from a side wall of the first casing 3 so as to come intocontact with the side wall 4 c of the second casing 4, but so that theprotrusion 3 c protrudes from the side wall 4 c of the second casing 4so as to come into contact with the side wall of the first casing 3.

Furthermore, instead of the protrusion 3 c, a protrusion electricallyconnected to a back face of a top plate of the second casing 4 may beprovided in an upper end face of the side wall of the first casing 3 towhich the optical pickup part 8 a makes a closest approach. That is, ata portion between the first casing 3 and the second casing 4 where theremay arise a gap due to the closest approach of the optical pickup part 8a, a protrusion for maintaining electrical connection may be provided.

FIG. 6 is a perspective view showing a positional relationship betweenthe first casing and the printed wiring substrate of the control circuitblock. FIG. 7 is a perspective view showing a state in which the printedwiring substrate is excluded in FIG. 6. FIG. 8 is a schematic sectionalview showing a structure of an interfacing connector portion in thecontrol circuit block.

As shown in FIGS. 6, 7 and 8, at a portion of the bottom of the firstcasing 3 corresponding to the connector 11 b mounted on the printedwiring substrate 10, an opening 3 d is provided for allowing theconnector 11 b to protrude outward of the first casing 3. A flat cable12, which is a cable for external connection to fulfill transmission andreception of signals to and from external electronic equipment (notshown), is inserted into the connector 11 b protruding from the opening3 d.

Also, the opening 3 d of the first casing 3 is formed at a bottomportion of a recess portion 3 e recessed from outside to inside of thefirst casing 3. The recess portion 3 e is sized so as to accommodate theconnector 11 b protruding from the opening 3 d so that the connector 11b is prevented from extending beyond the bottom face of the first casing3.

Further, a surface 3 f which is a portion of the recess portion 3 e foraccommodating the connector 11 b therein and along which the flat cable12 inserted into the connector 11 b extends is formed as a surfacesloped from the bottom portion of the recess portion 3 e toward an outersurface of the first casing 3. By laying down the flat cable 12 alongthe sloped surface 3 f so that the flat cable 12 is inserted into theconnector 11 b protruding from the opening 3 d, the flat cable 12 caneasily be electrically connected to the connector 11 b. For practicalimplementation of this, the connector 11 b has an insertion opening intowhich the flat cable 12 is inserted in a direction crossing with,preferably orthogonal to, the direction in which the connector 11 bprotrudes from the opening 3 d.

According to such an interconnection structure around the connector 11 bas described above, the flat cable 12 can be provided so as to extendfrom the connector 11 b while being kept along the first casing 3, whichis an electric conductor. In this case, a loop area over which a commonmode current flows in the flat cable 12 can be reduced. As a result,radiation noise generated from the flat cable 12 can be reduced, so thatradiation noise generated from the optical disc drive device can bereduced.

Further, since the opening 3 d that allows the connector 11 b toprotrude is formed at a bottom portion of the recess portion 3 erecessed inward of the first casing 3, the connector 11 b can be placedso as not to extend beyond the bottom face of the first casing 3.

In this embodiment, the opening 3 d of the first casing 3 is formed at abottom portion of the recess portion 3 e. However, the presentdisclosure is not limited to this. For example, the opening 3 d thatallows the connector 11 b of the printed wiring substrate 10 to beprotruded outward may be formed in the first casing 3 without formingthe recess portion 3 e.

Further, the external connection cable connected to the connector 11 band laid down along the sloped surface 3 f of the recess portion 3 e ofthe first casing 3 is not limited to the flat cable 12.

As described above and as shown in FIG. 8, the printed wiring substrate10 is screwed to the fitting portions 3 b of the first casing 3 withscrews 13. More specifically, the printed wiring substrate 10 is fixedto the first casing 3 in a state in which the ground pattern 10 a formedaround the connector 11 b is in electrical contact with the fringeportion of the opening 3 d of the first casing 3.

FIG. 9 is a schematic view showing a contact state between the fringeportion of the opening 3 d of the first casing 3 and the ground pattern10 a of the printed wiring substrate 10. As shown in FIG. 9, the groundpattern 10 a of the printed wiring substrate 10 is fixed to the fittingportions 3 b of the first casing 3 with the screws 13, and therebymaintained in a state of electrical contact with the bottom portion (aportion indicated by area A) of the recess portion 3 e, which is afringe portion of the opening 3 d of the first casing 3.

According to such an interconnection structure around the connector 11 bas described above, the ground pattern 10 a of the printed wiringsubstrate 10 is securely electrically connected to the exterior casing1. Also, the ground pattern 10 a of the printed wiring substrate 10 isformed so as to surround the periphery of the connector 11 b, cominginto electrical contact with the first casing 3. Therefore, release ofradiation noise to the outside between the connector 11 b and theopening 3 d can be reduced. That is, the connector 11 b protrudes fromthe opening 3 d in a state that shielding is provided between theconnector 11 b and the opening 3 d. In addition to this, intrusion offoreign matters into the exterior casing 1 between the connector 11 band the opening 3 d can be suppressed.

As described hereinabove, according to this embodiment, in the opticaldisc drive device, radiation noise to the outside can be reduced.Further, by virtue of the structure in which radiation noise isstructurally reduced, an optical disc drive device showing lessvariations in the radiation noise reduction effect can be provided.

Although the present disclosure has been fully described in connectionwith the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such Changes andmodifications are to be understood as included within the scope of thepresent disclosures as defined by the appended claims unless they departtherefrom.

What is claimed is:
 1. An optical disc driving device comprising: ametallic exterior casing including a first casing and a second casing;and an internal unit housed within said exterior casing, said internalunit including an optical pickup unit having an optical pickup partconfigured to move in a radial direction with respect to an optical discto be loaded in said optical disc driving device so as to performrecording or reproduction of information signals on the optical disc;wherein one of said first casing and said second casing has a protrusionprotruding toward the other of said first casing and said second casingso as to electrically connect said first casing to said second casing,said protrusion being located on a portion of said one of said firstcasing and said second casing closest to said optical pickup part whensaid optical pickup part has moved radially outward of the optical disc.2. The optical disc driving device according to claim 1, wherein: saidfirst casing is box-shaped; said second casing is lid-shaped so as toengage with said first casing; and said portion is opposed to a discinsertion opening for receiving an optical disc to be inserted therein,said portion being located in a side wall of said first casing or a sidewall of said second casing.
 3. The optical disc driving device accordingto claim 2, wherein said exterior casing is configured such that a frontportion of said second casing on a first side closest to said discinsertion opening is hooked to a front portion of said first casing, arear portion of said second casing is laid on a rear portion of saidfirst casing, and said rear portion of said second casing is screwed tosaid rear portion of said first casing with a screw.
 4. The optical discdriving device according to claim 3, wherein: said rear portion of saidsecond casing and said rear portion of said first casing are screwedtogether with two screws; and said protrusion is provided at either saidside wall of said first casing or said side wall of said second casingat an intermediate position between said two screws.
 5. An optical discdriving device comprising: a metallic exterior casing including a firstcasing and a second casing; and an internal unit housed within saidexterior casing, said internal unit including an optical pickup unithaving an optical pickup part configured to move in a radial directionwith respect to an optical disc to be loaded in said optical discdriving device so as to perform recording or reproduction of informationsignals on the optical disc; wherein one of said first casing and saidsecond casing has a protrusion protruding toward the other of said firstcasing and said second casing so as to electrically connect said firstcasing to said second casing, said protrusion being located on a portionof said one of said first casing and said second casing closest to saidoptical pickup part when said optical pickup part has moved radiallyoutward of the optical disc; wherein said exterior casing is configuredsuch that a front portion of said second casing on a first side ishooked to a front portion of said first casing, a rear portion of saidsecond casing is laid on a rear portion of said first casing, and saidrear portion of said second casing is screwed to said rear portion ofsaid first casing with a screw.
 6. The optical disc driving deviceaccording to claim 5, wherein: said rear portion of said second casingand said rear portion of said first casing are screwed together with twoscrews; and said protrusion is provided at either a side wall of saidfirst casing or a side wall of said second casing at an intermediateposition between said two screws.